1. Technical Field
The present invention relates to cosmetics containing a composite powder obtained by depositing fine particles of titanium dioxide or the like on a surface of a scale-like base material, and more specifically relates to make-up cosmetics containing such a composite powder.
2. Background Technology
Generally, a scale-like powder made from mica, talc, sericite and the like is blended in make-up cosmetics such as powder foundations. When the scale-like powder is blended in the cosmetics, adhesiveness to and extendability of the cosmetics on a human skin are improved, and an appropriate glossy effect is given to a cosmetic film applied on the human skin. Therefore, the scale-like powder is indispensable for the make-up cosmetics.
Furthermore, in addition to the adhesiveness, extendability, and glossy effect as described above, it is required for the make-up cosmetics that;    (1) a homogeneous cosmetic film is formed on a human skin;    (2) an appropriate covering capability is provided; and    (3) a white masking is not appeared, even when a cosmetic film applied on a facial skin is looked from a specific angle.
Moreover, a soft-focusing capability and an ultraviolet protective capability are often required for the cosmetics.
The scale-like powder itself does not have a high covering capability, and therefore generally fine particles of titanium dioxide (as a white pigment) are blended in the cosmetics.
However, it is known that because the fine particles of titanium dioxide have a high covering capability, sometimes the cosmetics film formed on a human skin, in particular a facial skin, causes a white masking when it is looked from a specific angle, even when a foundation with a color adjusted to a color of the human skin is used. In addition, because the fine particles of titanium dioxide is relatively small, for instance with an average particle diameter of around 0.3 μm, it is difficult to prepare powdery cosmetics containing the fine particles homogeneously dispersed therein. Furthermore, sometimes the fine particles of titanium dioxide are present in the cosmetics in the state of those partially aggregated. For this reason, when the cosmetics are applied on a human skin, a remarkable whiteness may occur on the human skin at the places where the aggregated particles are collapsed when rubbed by hand or in areas around such places, although the whiteness is not so remarkable in the appearance of the cosmetics. Namely, sometimes the color appearance of the cosmetics is largely different from a color tone of the cosmetic film when the cosmetics are applied on the human skin. Furthermore, when the cosmetics are applied on a human skin, some persons may feel unsmoothness or squeakiness due to the fine particles of titanium dioxide, which may spoils the skin feelings in use of the cosmetics, for instance in the extendability or adhesiveness as described above.
To overcome the problems as described above, there has been proposed an extender pigment for cosmetics, which is prepared by depositing fine particles of titanium dioxide (as a white pigment) on a surface of a scale-like base material, to give a comfortable feeling to the human skin and also an excellent covering capability to the cosmetic film (Reference is made to Patent document 1). However, the extender pigment itself has not the ultraviolet protective capability and as the color is white, sometimes the cosmetics film formed on a human skin, in particular a facial skin, causes a white masking as described above. Therefore, all of the basic properties required for the make-up cosmetics are not obtained by using such an extender pigment.
The scale-like powder does not protect the human skin against ultraviolet rays, and therefore, to give the ultraviolet protective effect to cosmetics, an organic ultraviolet absorber or fine particles of titanium dioxide having a particle diameter of several tens nanometer as the primary particle size (hereinafter referred to as “nanoparticles of titanium dioxide”) with an ultraviolet protective capability are often blended in the cosmetics. However, as the organic ultraviolet absorber causes a skin irritation, there is an upper limit to the amount of such ultraviolet absorber in practical use. Also, the average particle diameter of the nanoparticles of titanium dioxide is smaller than the fine particles of titanium dioxide as described above (namely, the average particle diameter of the nanoparticles of titanium dioxide is about several tens nanometer, while that of the fine particles of titanium dioxide is around 0.3 μm), and therefore it is extremely difficult to homogeneously disperse the nanoparticles of titanium dioxide in cosmetics such as powdery foundations. Furthermore, as the nanoparticles of titanium dioxide are often present in the aggregated state in several portions of the cosmetics, sometimes a color appearance of the cosmetics is substantially different from a color tone of the cosmetic film, like in the case of the fine particles of titanium dioxide as described above. Moreover, when the cosmetics are applied onto a human skin, many persons may feel unsmoothness or squeakiness strongly due to the nanoparticles of titanium dioxide, which may substantially spoils the skin feelings in use of the cosmetics, for instance in the extendability or adhesiveness as described above.
As described above, it is known that although various types of raw materials (such as extender pigments or color pigments) to be used in make-up cosmetics or the like show certain effects with the roles of the raw materials, such materials have various defects as described above. To overcome the problems, recent cosmetic manufacturers tend to prepare, by making the blending ratios of various raw materials in a balanced level, the cosmetics having the basic properties as described above, namely (a) an excellent adhesiveness, (b) an excellent extendability, (c) an appropriate glossy effect, (d) a homogeneous cosmetic film, (e) an appropriate covering capability, (f) a cosmetic film not causing a white masking, (g) a high compatibility between a color appearance of cosmetics and a color tone of the cosmetic film, (h) an excellent soft-focusing capability, (i) an excellent ultraviolet protective effect and the like. However, a sophisticated blending technique to obtain such basic properties as described above is required for preparation of the cosmetics. Even when the sophisticated blending technique is employed, it is not always possible to satisfy all of the above basic properties required for the cosmetics.
Patent document 1: Japanese Patent No. 3745688